The goal of this proposal is to explore the molecular mechanism as to why oligodendrocytes (OGs) prefer necroptosis, a regulated necrotic cell death pathway, as the primary cell death mechanism and the contribution of this pathway to progressive demyelination, inflammation and neurodegeneration in animal models of multiple sclerosis (MS). MS, an inflammatory demyelinating disease of the central nervous system (CNS), is the most common chronic neurodegenerative disease for young adults during their most productive ages. While the immunological basis of MS has been studied extensively, we still know very little about the mechanism that leads to the degeneration of OGs, the myelin producing cells that play a critical role in the maintenance of activity and integrity of neuronal axons. Preventing the death of OGs might be able to inhibit demyelination and axonal degeneration, the major cause of irreversible neurological disability in patients with progressive MS. Activation of TNFR1 by TNFalpha has recently been shown to mediate two alternative cell death pathways: caspase-dependent apoptosis and caspase-independent RIP1 kinase-dependent necroptosis (programmed necrosis). However, for most cell types analyzed so far, necroptosis is only activated when the activation of caspases is inhibited by chemical inhibitors or by genetic mutation. Interestingly, we found that OGs undergo necroptosis upon stimulation by TNFalpha alone which can be effectively blocked by Nec-1 or by RIP3 deficiency. We have shown that 7-Cl-O-necrostatin-1 (7-Cl-O-Nec-1), a highly specific inhibitor of RIP1 kinase, protects against TNFalpha-induced oligodendrocyte death in vitro and two mouse models of MS in vivo [cuprizone model and experimental autoimmune encephalomyelitis model (EAE)]. In addition, RIP3-/- mice are also resistant to cuprizone model and RIP3-/- OGs are protected against TNFalpha. We propose to investigate as to why OGs prefer to use necroptosis as the primary cell death pathway and the role and mechanism of RIP1 kinase in mediating the death of OGs.
Specific Aim 1 is to investigate the role and mechanism by which cellular metabolism and redox state control the sensitivity of OGs to TNFalpha. This is to test the hypothesis that the cell-cell interaction regulated high metabolic activity in OGs provides a critical mechanism that controls redox state and the sensitivity of OGs to TNFalpha mediated necroptosis.
Specific Aim 2 is to investigate the role of S-nitrosylation in regulating the sensitivity of OGs to TNFalpha induced cell death. This is to test the hypothesis that elevated nitrosylation stress in TNFalpha stimulated OGs leads to the inhibition of caspases and sensitization of OGs to necroptosis.
Specific Aim 3 is to examine the involvement of RIP1 kinase in mediating necroptosis of OGs in vivo and in vitro using RIP1 kinase dead knockin mutant mice. Our study may provide a strong rationale for the development of RIP1 kinase inhibitors as an OG protective strategy for the treatment of MS, and an orally available, highly specific and nontoxic RIP1 kinase inhibitor, 7-Cl-O-Nec-1, as a lead compound.

Public Health Relevance

The goal of this proposal is to explore the role and mechanism of necroptosis in mediating oligodendrocyte cell death induced by TNFalpha and the contribution of this pathway to progressive demyelination, inflammation and neurodegeneration in animal models of multiple sclerosis (MS). MS, an inflammatory demyelinating disease of the central nervous system (CNS), is the most common chronic neurodegenerative disease for young adults during their most productive ages. We propose to use necrostatins and genetic models and cellular and biochemical approaches to investigate the role and mechanism of RIP1 kinases in mediating the death of oligodendrocytes in TNFR1 pathway and the involvement of necroptosis in demyelination, inflammation and neurodegeneration in animal models of MS.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS082257-05
Application #
9301045
Study Section
Neural Oxidative Metabolism and Death Study Section (NOMD)
Program Officer
Gubitz, Amelie
Project Start
2013-09-15
Project End
2018-05-31
Budget Start
2017-06-01
Budget End
2018-05-31
Support Year
5
Fiscal Year
2017
Total Cost
$370,781
Indirect Cost
$152,031
Name
Harvard Medical School
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
047006379
City
Boston
State
MA
Country
United States
Zip Code
02115
Zhu, Kezhou; Liang, Wei; Ma, Zaijun et al. (2018) Necroptosis promotes cell-autonomous activation of proinflammatory cytokine gene expression. Cell Death Dis 9:500
Meng, Huyan; Liu, Zhen; Li, Xingyan et al. (2018) Death-domain dimerization-mediated activation of RIPK1 controls necroptosis and RIPK1-dependent apoptosis. Proc Natl Acad Sci U S A 115:E2001-E2009
Xu, Daichao; Jin, Taijie; Zhu, Hong et al. (2018) TBK1 Suppresses RIPK1-Driven Apoptosis and Inflammation during Development and in Aging. Cell 174:1477-1491.e19
Shan, Bing; Pan, Heling; Najafov, Ayaz et al. (2018) Necroptosis in development and diseases. Genes Dev 32:327-340
Amin, Palak; Florez, Marcus; Najafov, Ayaz et al. (2018) Regulation of a distinct activated RIPK1 intermediate bridging complex I and complex II in TNF?-mediated apoptosis. Proc Natl Acad Sci U S A 115:E5944-E5953
Dziedzic, Slawomir A; Su, Zhenyi; Jean Barrett, Vica et al. (2018) ABIN-1 regulates RIPK1 activation by linking Met1 ubiquitylation with Lys63 deubiquitylation in TNF-RSC. Nat Cell Biol 20:58-68
Su, Zhenyi; Dziedzic, Slawomir A; Hu, Die et al. (2018) ABIN-1 heterozygosity sensitizes to innate immune response in both RIPK1-dependent and RIPK1-independent manner. Cell Death Differ :
Geng, Jiefei; Ito, Yasushi; Shi, Linyu et al. (2017) Regulation of RIPK1 activation by TAK1-mediated phosphorylation dictates apoptosis and necroptosis. Nat Commun 8:359
Ofengeim, Dimitry; Mazzitelli, Sonia; Ito, Yasushi et al. (2017) RIPK1 mediates a disease-associated microglial response in Alzheimer's disease. Proc Natl Acad Sci U S A 114:E8788-E8797
Li, Ying; Qian, Lihui; Yuan, Junying (2017) Small molecule probes for cellular death machines. Curr Opin Chem Biol 39:74-82

Showing the most recent 10 out of 27 publications